Cushioning device for reversing mechanism



May l5, 1923. 1,454,987

` H.E. TowNsr-:ND

A CUSHIONING DEVICE FOR REVERSING MECHANISM File June 17, 1922 2 Sheets-Sheet l "f nl um: uw

- 1,454,987 H. E. TOWNSEND CUSHIONING DEVICE FOR REVERSING MECHANISM Filed .Jun 1'?. 1922 2 sheets-sheet 2 May l5, 1923.

Y A.. ,I

vPatented May I UNITED', srArEs lrasees? Pars-NT orrlcs'.

maar Ii. 'rowNsInm or Esso: rnovinmrcn, mIoD ISLAND, AssIcNoa' 'ro snows 5 AND SHARPE MANUFACTURING COMPANY, OF PROVIDENCE,

couronner: or maroni: ISLAND.

RHODE ISLAND, A

, csIIIomNe Davies ron. aEvEasING'MEcnANIsM.

Application led June 17, 1922. Serial No. 569,135.

My invention relates-to improvementsin f cushioning devices for reversing and driving mechanisms for reciprocating loads..

eitainl machines, such as for example,

grinding machines, planers, etc., are pro-' vided with reciprocating tables which carry the Vwork or'the tool. In order.toperiodiY vcally reverse the direction of travel of the table it is lusual to provide a reversible clutch which may be automatically actuated to reverse the direction of rotation'of the driving member and hence the directionfof travel of the table. Whenever the clutch is actuated to reverse the direction of table travel it is apparent that a shock in the f driving mechanism occurs.- It is the-prevention of this shock and corresponding strain on the'gears and driving members at which my invention aims.

It is .thus onel object of pr'ovide a means by which the driven member is gradually retarded and accelerated, so that with the assistance of springs the shocks incidental to reversing are yieldingly cushioned. By the use of my spring actuated and screw controlled cushioning device, it is possible to greatly increase the speed at which the table may be driven, and hence the cutting rate and efficiency of the whole machine. 4 l

A further object of my .invention is to produce a smoother surface on the ground article. AOne reason for this vresult is that the usual shock and vibration isY greatly lessened thereby securing. aruniformity in Y grinding even-whemgrindiirigv at a greater Another object of my invention is to eliminate any necessity for vproviding for lost motion durin the reversing period. This is automatica y taken care of .by my yield- .in c gfheseandsuch other features of my in-l A'vention as may hereinafter appear be best understood from a description of one my invention to embodiment thereof, such as for instance is shown in the accompanying drawings which illustrate an adaptation of my invention to the reversing nechanism of a grinding m8..- chine.

In the drawings, Figure 1 is a front skeleton view of a grinding machine, showing the table, the clutch, the cushionin device,

. and the train of gearing leading to t e table,

Figure 2 is a detailed section ofthe cushioniiig device and its adjacent parts. Figure 3 is a crosssection of the cushioningvdevice along the lines 3-3 of Figure 2. igure 4 is a detailed sectional view of the traversing nut used in the cushioning device.

Figure 5 is a perspective view of one of a set of washers used in the cushioning device.

In the drawings, wherein like reference.

characters indicate like parts throughout, 1 is the body of the grinding machine on which is mounted the reciprocating table 2. The dogs 3 are adjustable longitudinally in a. runway 4 on the front edge of the table 2, and are adapted to'trip at the desired in'- tervals the long arm 5a of the reversing' lever 5. The reversing lever 5 is suitably mounted on thebody 1, and its shortarm 5,b is bi-v furcated and has mounted ateach end of the bifurcations 5 the inwardly projecting vextensions 5d which register in grooves 8a of the sliding clutch member 8. This clutch `member 8 is constructed to slide longitudi nally on the shaft 9 and is usually splined .thereto (Fig. 2). It has onopposite ends the clutch faces 8J and 8. Loosely mounted on the shaft 9, and spaced suiliciently apart for adequate movement of the short arm 5b of the reversing lever 5 are the clutch members 10 and 11. Thev clutch `members 10 and 11 have cut thereonthe beveled teeth 10a. f

and 1-1 and are constantly driven in opposite rotation by the bevel gear 12"which is mounted on and driven by the lfeedshaft 12 (as seen in Fig. 2 behind the' clutch).

The clutch members`10 and 11 have on their opposed faces the (clutchfacesv 10" and 111" for engagement with the clutch faces 8" and 8 of the clutch member `8. These clutch` faces, preferably comprise positively'engaging teeth. Itl is thus seen that when the clutch face 8is in engagement twith'the face 10" the shaft 9 is drivenin one' direction, but.

lioof` los ' the, driving shaft 9.

clutch face 8c is in engagement withv` the face 11b of the clutch member 11 the shaft 9 isv "through my interposed cushioning device,

. tail.

which forms a connecting unit of the drive and which l will now describe in more den the opposite side of the bushing 13 from the clutch member 11 I have keyed tothe shaft 9 a small pinion gear 14:. Meshing with 'this small pinion '14 is the gear 15 which is suitably mountedkon the` split casting 26, which forms the housing of my device and which l will explain later. The gear 15 has projecting longitudinali from one side thereof the large cylindrica sleeve .15a (Fig. 2) which encircles for the desired distance the shaft 16, which is journaled in extensions from the bracket 24, as explained later. As this longitudinally projecting sleeve 15avis formed integral' with the gear 15 it is rotated therewith. This longitudinally projecting sleeve has cut on its inner periphery the longitudinal grooves 15b and 15"", in the construction as shown in Figure 3 six innumber. Adapted to slide longitudinally between the shaft 16 and the longitudinally projecting sleeve 15 is thetraversing nut 17. This is cylindrical in shape and has on its outer periphery the central annular shoulder 17a, which has projecting radially' therefrom the splines 17ID as shown-in Fig. 3, three in number, adapted to register with and slide longitudinally in the alternate grooves 15b. The shoulder 17n has end faces 17C. yThe traversing. nut 17 is hollow and has y-cut on its inner-periphery the helical threads 17 d. which encircle the shaftl is the gear 18 which has formed'integral therewith and projecting longitudinally therefrom in thesame direct-ion as the cylindrical sleeve 15a projects from the gear 15, the sleeve 18a. This longitudinally projecting sleeve 18 has cut on its outer periphery the helical threads 18d, adapted to engage the helical threads 17d on the4 inner periphery of theV traversing nut 17. As seen in Fig. 2, the longitudinally projecting 'sleeve 15a approximately encloses lthe longitudinally projecting sleeve 18a. The traversing nut 17' is shorter than the longitudinal distance allotted to it between the sleeves 15u and 18, and is free to move lengthwise thereof, its longitudinal splines 17 being in engagement Mounted on the bushings 16a.4

insana? with the alternate longitudinalgrooves 15",

and its helical threads 17d being in engagement with the helical threads 18". When the lsleeve 15ao is revolved as the splines 17h are in engagement with th e grooves 15", driving force is exerted on the traversing nut 17. This force is resolved into two moments b the helical threads 17 d, one moment of whic tends to vforce the'traversing nut 17 longitudinally of the 'sleeves 15.a and 18a, while the other tends to rotate the longitudinal sleeve 18, This rotary moment is taken up .by the helical threads 18d thus rotating the longitudinally projecting sleeve 18a and its integral gear 18. l To yieldingly cushion the longltudlnal movement 'of the traversing nut 17, and toftake up the shocks of reversal. l provide the springs 19 and 1:9', shown eX tended and compressed respectively in F igure 2 `These springs 19 and 19 are coiled around the longitudinally projecting sleeve 18?.1 and are enclosed by the longitudinally projecting sleeve 15. Oneend of the spring 19 (Fig. 2) rests against a washer 19a which bears against one face 18c of the gear 18. One end ofthe spring 19 (Fig. 2) rests against a washer 19a lwhich bears against thethrust collar 20, The. othen ends of the springs 19 and 19 press against the washers 21, the opposite sides of which-contact the faces 17c of the traversing' nut 17. These washers 21 have projecting from their outer periphery the splines 21, as shown in Figure 5, three in number, adapted to slide longitudinally in the alternate grooves 15"' of the longitudinally projecting sleeve 15a (Fig. 3). Centrally of the alternate grooves 15b', and suitably secured therein by the rivets 22 are the keys 23 which extend longitudinally a short distance each side of the rivets 22 (Fi-g. 2), and limit the longitudinal movement of the Washers 21. This pre-y vents the springs 19 and 19 from becoming unduly extended and determines the point of reversal more accurately. It is apparent from the above that the springs 19 and 19 yieldingly limit thelongitudinal movement of the traversin nut 17 and are uniformly controlled in t threads 17dl and 18d. Though I have shown a method'of controlling the action of the elastic members 19 and 19 by the helically threaded screws 17d and 18, it is obvious that any other suitablemethod may be employed. v

As the cushioning effect of the springs 19I and 19 is increased as they are coinpressed, and thus the longitudinal movement .of the traversing nut 17 correspondingly decreased the rotary driving force of the helical threads 17d against the helicalthreads 181 of the longitudinally projectin sleeve 18a is correspondingly increased. hen the spring 19 is suiiiciently'compressed, the longitudinal movement of the traverse nut is i lit? stopped, and the rota force, transmitted from the longitudina y vprojecting .sleeve 15% to the nut 17 by the walls of the grooves 1 5" in the sleeve 15" comin into engagement with the splines 17" of te traversing nut 17, is brought to bear against the sleeve 18 by the interlocking of the helical threads 1 d the table 2 causes the normallyv driven gear 18 to act for -a short interval of time as a driving gear. This temporary driving motion is transmitted through 'the helical threads '18l and 17d to the traversing nut 17 and tends to drive it'back along the sleeve 18". AS the traversing nut 17 is thus driven against the-now extended spring 19 and this is partially compressed, itis apparent that the forward movement of the'table and its connecting members will be gradually and vwithout. shock retarded from the driving rate to temporary rest.

Though I have shown an intermediate member or traversing nut 17, it is clear that this element may be' omitted without departing from the spirit of my invention, for the driven member or sleeve 15a mi ht While being rotated be moved longitu inally of the driving member' against a yielding cushion and power transmitted in that fashion.

.My cushioning device may be sup orted and enclosed convenientl as fo lows: Mounted on the body 1 of the grinding machine is the bracket 24, which supperts the bearings 24a in which is journaled the shaft 16. As stated the longitudinally projecting ,sleeve 18a rotates on bus ngs 16 supported b? the shaft- 16. Enclosing the end ofv the s eeve 18a is the thrust collar 20 which is -held in position by the locknut 25. My

cushioning device is enclosed and supported by the housing 26, cast with a base 26 Aadapted to rest on the supporting bracket 24. The housing 26 sup orts the bushing 27 which surrounds the s eeve 15 and may be split as at 26" for convenient removal.

The upper portion of the split housing 26 usually has cast thereon an extension 26 adapted to receive the reduced portion 13a of the bushing 13. -Meshingwith the gear 18 (Fig'...1) is thepinion 30L 4formed at one end ofthe sleeve 30 which'` is rotatively mounted on, a' reduced extension 9a of the driving shaft 9`and secured thereto by a' locknut, as shown. On theopposite end of this sleeve 30 is'ja bevelgear 30" which.

meshes with a bevel gear 31a-,keyed to one.

end of the shaft 31.- The shaftl 31 has keyed at'v its oppositeend, disposed Vin front .of the cushioning device and shaft-9,'the pinand 18", and the lgear 18, is rotated' vvat a constant rate. The yielding cushion ion 31". The pinion 31" with the I gear 32 (shown in Fig. 1 pa'tiall broken away) keyed to the shaft 32 w ich has keye at its rear end the small pinion 32". This inion 32" meshes with a gear 33 supporte in a bracket 34 which extends from the body 1 of the grinding machine. The gear 33 in turn meshes with the rack .35 of the table 2. Y

Figure 1 illustrates the clutch member 8 in neutral position. Figure 2 illustrates the clutch member 8 in driving en gement with the co-operatin clutch--memer 10, with the table 2 being driven at the desired uniform rate asthe spring 19 is shown compressed.

In operation the clutch member 8 is moved b the short arm 5" of the reversing lever 5 rom driving engagement with the clutch member 11 to driving engagement with the clutch member 10. The direction.

of rotation of the shaft 9 is immediately Jreversed and this reversal of motion is imof the splines 17b 'of the traversing nut 17.

As the helical threads 17l and 18i are of relatively low pitch the vforce of the then compressed spring 19 is not suicient to throw the traversing nut back along the sleeve 18". As stated, rotative force vis brought to bear on the traversing nut 17. As the helical threads 17d are inclined this ressure tends both to move the nut 17 ongitudinally of the sleeve 18s,'and to exert a straight rotary driving pressure on the sleeve 18 through the medium of the threads 18d. The longitudinal movement tends to drive the traversing nut 17 longitudinally of the sleeve18. There 'is however a small amount of rotary driving force always, exerted against the sleeve 18. The; face 1 7c of the traversing nut 1 7- now strikes against the washer 21, and the spring 19 bearing against the washer 21 resents a yielding cushioning resistance to t e further longitudinal movement of the traversing` los' is furl correspondresistance to the longitudinal Amovement of the nut 17 and vrender uniform the resistanceof the elastic member 19. It is obvious that the spring '19 yprovidesgin addition a means whereby the' initial starting-shock 'mentum in the same direction.`

s the train of gearing to the gear 18. lThis lnormally driven member thusacts for a short interval of time as a driving member, and the threads 18d bearing against the threads 17d of the traversing nut 17 tend to drive it back along the sleeve 18a. As this is driven against the now extended spring 19 and the spring 19 partially compressed, it is apparent that the forward movement of the table and its connecting members, will. be gradually and without shock retarded -from the driving rate to temporary rest. ,Then the driving action of the sleeve l5 brings itself to bear against the traversing nut 17, and the driving motion .is yieldingly accelerated as explained. lt is seen that as the rotation. of the shaft 9 is reversed, this reversing motion andshock will be repeatedly cushioned and the rotary motion imparted from said shaft will be at iirst acceleratingly, then uniformly for the desired period of the table travel and finally retardlngly transmitted to the table 2, the springs 19 and 19 being alternately compressed at each reversal of the table. This operation is repeated in running the machine.

at l claim as new and ,desire to secure as Letters Patent, is-

1. A cushioned reversing and driving mechanism for reciprocating loads, having in combination, a clutch mechanism for rotating a shaft alternately in opposite directions, a longitudinally 'extending cushionenclosing sleeve, means for engaging this sleeve with the driving shaft to impart rotary motion thereto, grooves formed on. the inner periphery of said sleeve, a hollow cylindrical traversing nut containing on its l f outer periphery splines to engage the grooves in said sleeve, and threads on its inner periphery, a threaded sleeve adapted to engage vthe threads on the inner periphery of said traversing nut, a set of springs coiled around the threaded sleeve and enclosed by the grooved sleeve, washers intermediate said springs and traversing nut, and means extending from the threaded sleeve to drive the reciprocating load.

2. A cushion reversing and ery of said traversing nut, a set of springs coiled around the threaded sleeve and enclosed by the grooved sleeve, washers inter mediate said springs and traversing nut, keys secured medially the alternate grooves of the grooved sleeve, and means extending Irom'the `threaded sleeve to drive the reciprocating load.

3. A cushioned reversing and driving mechanism for reciprocating loads, having' in combination, a clutch mechanism for rotating a shaft alternately in opposite direc'- tions, a longitudinally extending cushion-enclosing sleeve, means for engaging this sleeve with the driving shaft to impart rotary motion to said sleeve, grooves formed on the inner periphery of said sleeve, a hollow cylindrlcal traversin nut containing on its outer periphery splines to engage the grooves in said sleeve and threads on its inner periphery, a threaded sleeve adapted to engage the threads on the inner eriphery o said traversing nut, a set of springs coiled around the threaded sleeve and enclosed by the grooved sleeve, and means extending from the threed sleeve to drive the reciprocating loads d.. A cushioned reversing and driving mechanism for reciprocating loads, having in combination, a clutch mechanism for rotating a shaft alternately in opposite directions, a rotary cover, means for engaging this cover with the driving shaft to impart rotary motion thereto, grooves formed on the inner periphery of said cover, a longitudinally movable connecting member containing on its outer periphery splines to engage the grooves in said cover and helical threads on its inner periphery, a rotary internal member helically threaded to engage the helical threads on the inner periphery of said .connecting member, spring means adapted to longitudinally encircle the internal member and be enclosed by the cover,4 and means to transmit the power from the internal member to the reciprocatin load.

In testimony whereof I aiiix my signature.

HERBERT E. Townsmen.-v 

